The diversity of modern technical applications creates a need for efficient electronic components and integrated circuits for use therein. Capacitors are a fundamental component used for filtering, decoupling, bypassing and other aspects of such modern applications which may include wireless communications, alarm systems, radar systems, circuit switching, matching networks, and many others. The incredible variety of capacitor environments implies that capacitors are often subjected to a number of different operating frequencies. Capacitor technology that can accommodate applications at conventional frequency levels as well as increasing higher frequency applications such as related to wireless communications systems, including satellite, GPS, and cellular applications, must exhibit reliable performance characteristics over a generally wide frequency range.
There are many different performance characteristics of a capacitor for which improvement may be sought to facilitate desired operation. Selected of such characteristics may include high capacitance, small component footprint, robust mechanical assembly, and predictable frequency response over a wide range of frequencies. Achieving many or all of these desired characteristics in a single monolithic structure would help to provide a beneficial capacitive device.
A need for various different performance characteristics in a single electronic component is one of many reasons that previous combinations of multiple capacitors or other devices into a monolithic structure have been made, various known examples of which will now be mentioned.
One example of technology that addresses certain capacitor performance aspects is disclosed in U.S. Pat. No. 5,973,907 (Reed). Reed concerns a multiple element capacitor with different capacitors having common terminals in a case. Exemplary embodiments are designed to exhibit capacitance values of greater than about 0.1 μF and impedance/ESR values that are relatively flat over certain given frequencies.
Additional references that disclose exemplary technology with aspects of component design including size and/or spacing that may be controlled to allow for preselection of desired operative capacitor characteristics include U.S. Pat. Nos. 6,487,064, 6,337,791, and 5,576,926 (Monsarno). Such Monsarno references generally concern internal electrode capacitor embodiments often designed and utilized for desirable high frequency behaviors.
U.S. Pat. No. 5,687,056 (Harshe et al.) discloses chip capacitor devices having various voltage and capacitance properties and lead pins electrically coupled to a capacitor assembly. Exemplary devices include a plurality of capacitor subassemblies arranged in a generally stacked configuration. U.S. Pat. No. 5,355,277 (Hoshiba) concerns a thin film capacitor including a first capacitor composed of a ferroelectric film and a supplemental secondary capacitor composed of a film surrounding the first capacitor.
Other examples of component assemblies featuring one or more integrated capacitor portions can be found in U.S. Pat. No. 5,367,437 (Anderson), U.S. Pat. No. 4,124,876 (Labadie et al.), and U.S. Pat. No. 3,670,222 (Nakata et al.). Anderson discloses multiple layer capacitors stacked on top of one another and then provided in a clamped array formation for subsequent surface mounting. Labadie et al. concerns a modular capacitor made of two elementary capacitors (same or disparate valued) with common leads placed between the capacitors. Such modular arrangement is intended to provide highly accurate capacitance values and high mechanical strength. Nakata et al. discloses an exemplary ceramic capacitor assembly comprising a plurality of ceramic capacitor blocks disposed in a stacked relationship within a tubular insulating housing.
Exemplary background references in addition to those already cited include U.S. Pat. No. 6,212,060 (Liu), U.S. Pat. No. 6,077,715 (Chivukula), U.S. Pat. No. 5,777,839 (Sameshima et al.), U.S. Pat. No. 5,204,546 (Moulding), U.S. Pat. No. 4,827,323 (Tigelaar et al.) and U.S. Pat. No. 4,661,884 (Seaman).
The disclosures of all the foregoing United States patents are hereby fully incorporated for all purposes into this application by reference thereto.